Since GaN is a material having a wide band gap, a high breakdown field intensity and a high saturation electron speed, GaN is very promising as a material capable of implementing a device (semiconductor device) of great current, a high voltage and low on-resistance operation.
Therefore, development of a GaN-based HEMT (High Electron Mobility Transistor) in which GaN is used as an electron transit layer is being performed lively.
Conventionally, as a GaN-based HEMT (GaN-HEMT), development of an AlGaN/GaN-HEMT in which GaN and AlGaN are used for an electron transit layer and an electron supply layer, respectively, and an AlGaN/GaN heterojunction is utilized is being performed lively.